@article{10_4064_cm_21_2_179_186,
     author = {Ernest P{\l}onka},
     title = {Symmetric operations in groups},
     journal = {Colloquium Mathematicum},
     pages = {179--186},
     publisher = {mathdoc},
     volume = {21},
     number = {2},
     year = {1970},
     doi = {10.4064/cm-21-2-179-186},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-21-2-179-186/}
}